A large and growing population of people is enjoying entertainment through consumption of digital content items, such as music, movies, images, books and so on. Many people today consume digital content through a wide variety of electronic devices, including optical projectors or other projection devices.
Laser beams may be used to by certain projection systems to project visual images onto projection surfaces. Laser-based projection systems have advantages over more traditional projection techniques, including the ability to package such systems in relatively small form factors.
Despite the advantages of laser-based projection systems, there is concern over their safety. In particular, laser beams of sufficient brightness may cause damage if directed through the pupil of a human eye.
An acceptable exposure limit (AEL) for lasers is defined by the International Electrotechnical Commission (IEC) by measuring the energy of the laser beam through a measurement aperture having a diameter of 7 millimeters, at a distance of 100 millimeters from the projection source. The AEL is expressed as a maximum power during an exposure time. The specified 7 millimeter diameter represents the maximum dilation of the human eye.